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8255368: Math.exp() gives wrong result for large values on x86 32-bit platforms

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Reviewed-by: darcy, kvn
This commit is contained in:
Xubo Zhang 2020-11-18 04:49:15 +00:00 committed by Sandhya Viswanathan
parent 7ecf070e7d
commit c08921487b
2 changed files with 72 additions and 8 deletions
src/hotspot/cpu/x86
macroAssembler_x86_exp.cpp
test/jdk/java/lang/Math
ExpCornerCaseTests.java

16
src/hotspot/cpu/x86/macroAssembler_x86_exp.cpp

@ -493,7 +493,7 @@ void MacroAssembler::fast_exp(XMMRegister xmm0, XMMRegister xmm1, XMMRegister xm
subl(rsp, 120);
movl(Address(rsp, 64), tmp);
lea(tmp, ExternalAddress(static_const_table));
movdqu(xmm0, Address(rsp, 128));
movsd(xmm0, Address(rsp, 128));
unpcklpd(xmm0, xmm0);
movdqu(xmm1, Address(tmp, 64)); // 0x652b82feUL, 0x40571547UL, 0x652b82feUL, 0x40571547UL
movdqu(xmm6, Address(tmp, 48)); // 0x00000000UL, 0x43380000UL, 0x00000000UL, 0x43380000UL
@ -585,18 +585,18 @@ void MacroAssembler::fast_exp(XMMRegister xmm0, XMMRegister xmm1, XMMRegister xm
pextrw(ecx, xmm0, 3);
andl(ecx, 32752);
cmpl(ecx, 32752);
jcc(Assembler::greaterEqual, L_2TAG_PACKET_3_0_2);
jcc(Assembler::aboveEqual, L_2TAG_PACKET_3_0_2);
cmpl(ecx, 0);
jcc(Assembler::equal, L_2TAG_PACKET_4_0_2);
jmp(L_2TAG_PACKET_2_0_2);
cmpl(ecx, INT_MIN);
jcc(Assembler::less, L_2TAG_PACKET_3_0_2);
jcc(Assembler::below, L_2TAG_PACKET_3_0_2);
cmpl(ecx, -1064950997);
jcc(Assembler::less, L_2TAG_PACKET_2_0_2);
jcc(Assembler::greater, L_2TAG_PACKET_4_0_2);
jcc(Assembler::below, L_2TAG_PACKET_2_0_2);
jcc(Assembler::above, L_2TAG_PACKET_4_0_2);
movl(edx, Address(rsp, 128));
cmpl(edx, -17155601);
jcc(Assembler::less, L_2TAG_PACKET_2_0_2);
jcc(Assembler::below, L_2TAG_PACKET_2_0_2);
jmp(L_2TAG_PACKET_4_0_2);
bind(L_2TAG_PACKET_3_0_2);
@ -614,10 +614,10 @@ void MacroAssembler::fast_exp(XMMRegister xmm0, XMMRegister xmm1, XMMRegister xm
bind(L_2TAG_PACKET_7_0_2);
cmpl(eax, 2146435072);
jcc(Assembler::greaterEqual, L_2TAG_PACKET_8_0_2);
jcc(Assembler::aboveEqual, L_2TAG_PACKET_8_0_2);
movl(eax, Address(rsp, 132));
cmpl(eax, INT_MIN);
jcc(Assembler::greaterEqual, L_2TAG_PACKET_9_0_2);
jcc(Assembler::aboveEqual, L_2TAG_PACKET_9_0_2);
movsd(xmm0, Address(tmp, 1208)); // 0xffffffffUL, 0x7fefffffUL
mulsd(xmm0, xmm0);
movl(edx, 14);

64
test/jdk/java/lang/Math/ExpCornerCaseTests.java Normal file

@ -0,0 +1,64 @@
/*
* Copyright (c) 2011,2020, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* @test
* @bug 8255368
* @summary Tests corner cases of Math.exp
*/
public class ExpCornerCaseTests {
private ExpCornerCaseTests(){}
public static void main(String... args) {
int failures = 0;
failures += testExpCornerCases();
if (failures > 0) {
System.err.printf("Testing exp corner cases incurred %d failures.%n", failures);
throw new RuntimeException();
}
}
private static int testExpCornerCases() {
int failures = 0;
double [][] testCases = {
{+0x4.0p8, Double.POSITIVE_INFINITY},
{+0x2.71p12, Double.POSITIVE_INFINITY},
};
for (double[] testCase : testCases) {
failures += testExp(testCase[0], testCase[1]);
}
return failures;
}
private static int testExp(double input, double expected) {
int failures = 0;
failures += Tests.test("StrictMath.exp", input, StrictMath.exp(input), expected);
failures += Tests.test("Math.exp", input, Math.exp(input), expected);
return failures;
}
}